Method for producing profiled metal sheets

ABSTRACT

The present invention relates to a method for producing a profiled metal sheet, comprising the following steps in the indicated order: a) roll forming at least part of a sheet metal strip by means of a roll forming unit, wherein the sheet metal strip determines a first working plane of the roll forming unit, in respect to which parts of the sheet metal strip are bent up to form the profiled metal sheet, and wherein the bent parts of the sheet metal strip are curved at least partially in respect to the first working plane; and b) bending the profiled metal sheet by means of a bending unit, wherein the bent up parts of the profiled metal sheet are bent such that a second working plane is formed, wherein the first working plane becomes curved. The present invention thus provides an easy-to-implement, resource-conserving and cost-effective method.

The present invention relates to a method for producing a profiled metalsheet according to the features of claim 1.

Roll forming (cold roll fowling) is a continuous process in which aprofile is manufactured from a sheet metal strip. With this method,several processing steps can be performed simultaneously, such asembossing, cutting, decorating, perforating etc. This differentiatesroll forming from other techniques, such as extruding, trimming orbending pressing. An advantage of roll forming is that large series withthe same cross-section can be manufactured within a relatively shorttime. Different metals can be used during this process.

This method can also be employed for manufacturing profiles withvariable cross-sections, but considerable efforts are needed for thispurpose. If profiles with variable cross-sections are profiled, i. e.profiles which have cross-sections differing over their length, this canbe called flexible profiling.

Bending is a shaping manufacturing method. A bending moment is appliedto the material and causes a permanent deformation. Metal sheets arebent basically by folding of a surface portion with respect to theremaining surface of a sheet-metal strip. Depending on the methods andmachines employed, relevant characteristics of the workpiece, such asbending edge, bending angle or bending radius, are defined andreproducible.

The disadvantages of the prior art producing profiled metal sheets canbe summarized as follows. Flexible profiling cannot be achieved easilyand an easy guidance of a profile is not possible since contours to beguided must first be formed. Also, roll forming and variability inheight are coupled to another. Furthermore, with roll forming, thenecessary upsetting and extension deformations, for example, cannot beeasily introduced into a flexible cross-section. Also, it has not beenpossible to easily adapt the shape of the parts to the load up to thispoint. In addition, the machines used for bending, in particular thepresses, are relatively expensive.

The aim of the present invention is therefore to provide aneasy-to-implement, resource-conserving conserving and cost-effectivemethod by means of which the disadvantages of the prior art describedabove can be eliminated.

This aim is achieved by a method with the characterizing features ofclaim 1.

Advantageous further developments of the invention are indicated in thedependent claims.

A detailed description of the invention by means of the appendeddrawings will now follow wherein:

FIG. 1 shows some variants according to the invention and their formingmethods;

FIG. 2 shows some variants according to the invention from FIG. 1 andperspective views thereof, and

FIG. 3 shows a schematic presentation of a forming process according toone embodiment of the present invention.

The present invention refers to a method for producing a profiled metalsheet. The method comprises the following steps in the indicated order.In step a), roll forming of a sheet metal strip by means of aconventional or rigid roll forming unit or a flexible roll forming unitoperated like a conventional or rigid roll forming unit is performed.The sheet metal strip determines a first working plane of the rollforming unit in respect to which parts of the sheet metal strip are bentup to form the profiled metal sheet. In addition, the bent parts of thesheet metal strip are curved at least partially in respect to the firstworking plane. In step b), bending of the profiled metal sheet by meansof a bending unit is performed. In doing so, the bent up parts of theprofiled metal sheet are bent such that a second working plane is formedand the first working plane is curved.

The profiled metal sheets produced with the method according to theinvention can be open or closed. They can furthermore have a variablecross-section in the direction of their longitudinal axis. In addition,the profiles can be straight or bent.

In one embodiment, the method furthermore comprises a step c) after stepb). In step c), roll forming of the profiled metal sheet is carried outusing a conventional or rigid roll forming unit or a flexible rollforming unit operated like a conventional or rigid roll forming unit.Here as well, parts of the profiled metal sheet are bent up with respectto the second working plane. Also, in this step, roll forming comprisesa supporting measure. In one embodiment, the supporting measure can becarried out at the first working plane. For this purpose, individualrollers or roller pairs movable in at least one axis can follow theprofile contour in a controlled manner. During this process, the profilemust be supported after the (first) bending so that it can be guidedthrough the roll forming unit without any problems, such as deformation,during the subsequent roll forming process. There are differentsupporting possibilities.

One possibility is guiding or supporting in the roll forming unit bymeans of rollers or roller pairs. During this process, therollers/roller pairs must follow the new bent contour, i. e. they mustbe movable at least in one axis and able to track the contour with acorresponding control. With reference to the following embodiment, withthe top-hat profile, the bottom must be supported, depending on thecurrent height, with rollers which can track the longitudinal section inthe vertical direction. In each stand of the roll forming unit followingthe bending, the rollers or roller pairs can thus be moved in height forsupport.

Alternatively, the bent profile can also be placed and clamped in a kindof “negative mold” and guided through the roll forming unit on a linearguide. However, in this case, a continuously guided process is notpossible and the mold or molds must permanently be returned to the headof the unit.

In another embodiment, the method further comprises a step d) after stepc). In step d), the profiled metal sheet is bent by means of a bendingunit. During this process, the first and the second working plane are atleast partially curved.

In one embodiment, the bending in step b) can take place on one plane.In another embodiment, the bending in step d) can take place on oneplane, on two planes or on three planes. If bending takes place on twoplanes, for instance, new roll forming lines can be aligned at thebottom and on the side, which are then bent or formed, respectively, inthe subsequent roll forming process. If bending takes place on threeplanes, a torsion can be introduced into the profile.

In the method according to the invention, at least one dimension of thecross-section of the profiled metal sheet can be kept constant or vary.A repetitive combination of roll forming and bending allows theproduction of profiles and cross-sections in any desired variants. Thewidth and height can vary. Furthermore, angles can also be varied overthe length. Also, for example, in one roll forming step only one half ofthe metal sheet or the cross-section can be processed and in asubsequent roll forming step the other half. Only the order of the rollforming steps is important. Furthermore, as mentioned above, bending canalso take place in two or three dimensions (e. g. right/left, up/downand torsion).

In the method according to the invention, the profiled metal sheetscomprise the following profiles: straight or bent profiles, U-shapedprofiles with or without flanges, V-shaped profiles with or withoutflanges, C-shaped profiles, top-hat profiles, M-shaped profiles, ovalprofiles, rectangular profiles and combinations thereof Oval andrectangular profiles occur, for instance, in oval pipes or rectangularpipes, respectively.

In the method according to the invention, bending can comprise asupporting measure. As a supporting measure in the bending process, acore, a drawing die, a mold or glide-draw bending can be employed. Thebending process can also take place by means of a simple tool withinterior and exterior part in combination with a hydraulic press. Also,the rollers for a 3-roller bending process can contain suitablerecesses, brims and shoulders. Furthermore, the workpiece can also befilled with an elastic plastic material (e. g. silicone). In case ofwind instruments, for example, the pipe is filled with liquid leadbefore bending.

In the methods according to the invention, bending comprises theprocesses 3-roller bending, glide bending, bending with form shoe andstretch-bending. The present invention also envisages combinations ofthese processes.

With reference to FIG. 1, some variants according to the invention andtheir forming methods are shown. For manufacturing the profile A shownin cross-section four steps are required, namely a roll forming step 1,followed by a bending step 2, followed by another roll forming step 3and an additional bending step 4. These steps are explained in moredetail with reference to FIG. 3. In addition, the first two steps forproducing the profile B are analogous to those for producing profile A,followed by an additional roll forming step 3 and another bending step4. Similarly, steps 1 and 2 for manufacturing the profile C areanalogous to steps 1 and 2 for producing profile A, followed in turn byanother roll forming step 3 or bending step 4. Profile D in FIG. 1 isproduced by means of a roll fowling step 1, followed by a bending step 2and another bending step 4. Additionally, at the bottom of FIG. 1, alateral view of profiles C and D is shown, with pleats on the profilesides formed parallel to the bottom or the rim (flange).

In another embodiment which is not shown pleats are provided on theprofile sides in any position. These pleats also form a new roll formingline or plane. The orientation and position of the pleats is determinedby the definition of the new roll forming line (plane).

With reference to FIG. 2, the profiles A, B and C from FIG. 1 are shownas well as perspective views thereof, where the perspective views a1, a2show different bending variants of the profile A, the perspective view bshows a bending variant of the profile B and the perspective view eshows a bending variant of the profile C.

The profiled metal sheets produced according to the invention can beused in different industries, e. g. in the automotive industry,especially for frame longitudinal and transverse members, bumpers, doorstiffenings, preforms for inner high-pressure metal forming; inshipbuilding, particularly for masts; in road construction, especiallyfor lanterns; and in architecture, especially for structural steelprofiles.

The present invention further envisages a unit by means of which themethod according to the invention can be implemented. An embodiment ofthe unit can be as follows: in one module 1 of the unit, there can be aconventional roll forming unit which forms the sheet metal strip, cut tosize, according to step a) of the present invention (e. g. to a Uprofile). In a follow-up module 2, there can be a bending unit whichbends the profiled metal sheet from step a) according to step b) of thepresent invention. In another embodiment of the unit, there can beanother conventional roll forming unit in a module 3 downstream ofmodule 2, which further forms the profiled metal sheet from step b)according to step c) of the present invention (e. g. from a U profile toa top-hat profile). In another embodiment of the unit, a further bendingunit can be located in a module 4 downstream of module 3, which furtherbends the profiled metal sheet from step c) according to step d) of thepresent invention. In case the unit comprises the modules 1 through 4described above, a method according to the invention can be implementedwhich is explained in the following example of embodiment.

However, the unit according to the invention is neither limited to theabove-mentioned number of modules nor to the types thereof. In oneembodiment of the unit, for example, a feeding module and/or a cuttingmodule can be provided before the method according to the invention iscarried out. Furthermore, another cutting module can be provided e. g.after the method according to the invention has been completed.

The method according to the invention can be carried out in the unit ina continuous or a discontinuous process. As mentioned above, theprofiled metal sheets can also be bent, where the position of thebending line is critical for the process to be performed. If the bendingline is to be located in the cross-section of the metal sheet to beprofiled, a continuous process can take place (continuous unit). If, onthe other hand, the bending line is to be positioned outside thecross-section of the profiled metal sheet, a discontinuous process is totake place (discontinuous unit).

Exemplary Embodiment

With reference to FIG. 3, a schematic representation of a formingprocess according to an embodiment of the present invention is shown.Step 0 shows a top view of the respective profile A0 of a flat sheetmetal strip cut to size. Steps 1-4 show corresponding lateral views ofthe profile A1-A4 during forming. On the left side, the cross-sectionsof profiles A1-A4 are represented.

In step 1, the lateral wings can be bent, for instance, to a “U profile”on a first working plane 11 of a conventional roll forming unit. Bycutting the sheet metal to size, a U profile with variable a height ofthe lateral wings is produced.

In step 2, a variable bending process can be implemented, for instance,with an adapted COPRA® Flexform stand. The bending radius changescontinuously during this process. The strip edge lies flat against asecond working plane 21 over its entire length. It should be noted thatthe term “strip edge” refers to the presented example. In general, itshould be said that the new roll forming line(s) is/are brought to onelevel and aligned horizontally for the subsequent roll forming unit,respectively.

In step 3 of a conventional roll forming unit, the bent U profile can bebent, for example, to a “top-hat profile”. The rim of the “hat” lies onone plane and the lateral faces of the top-hat profile receive avariable height. Possibly, a discontinuous guidance of the bottom 33, e.g. with a simplified COPRA® Flexform stand, may be necessary.

In step 2 of the present example, the metal sheet is bent in only onedimension (up/down); however, it is also conceivable to bend the metalsheet in two or three dimensions. If the metal sheet is now bent in twodimensions, the new roll forming line, as in the case of bending in onedimension, passes horizontally through the roll forming unit in step 3,but due to the additional curvature in the second dimension, the standsof the subsequent roll forming unit must be adapted to this seconddimension.

In step 4, a variable bending process can be performed, for instance, bymeans of an adapted COPRA® Flexform stand. During bending, the bendingradius changes continuously. Eventually, the desired final profile shownin cross-section on the right side can be obtained.

The advantages achieved by the present invention can be summarized asfollows:

The methods roll forming (or respectively cold roll faulting) andbending are well-known and easy-to-implement methods, resulting in aneasy-to-implement method according to the invention.

In production, the profile to be formed can more easily be bent thanflexibly profiled.

In the bending process, a core or other supporting measures can beemployed.

Necessary upsetting and stretching processes in the flexiblecross-section are introduced by the bending process, resulting in acost-effective method according to the invention. In this way, therequired guiding of the cross-section or of the profile, respectively,can also be implemented more cost-effectively.

A shape of the components which is adapted to the load (savings in termsof weight and expenditure of energy) can be obtained easily, resultingin a resource-conserving method according to the invention.

Roll forming and variability in height are decoupled.

Easier guidance of the profile is possible since the contour to beguided already exists. In contrast, the contour necessary for guiding isonly being produced in the course of a flexible profiling process.

By appropriate selection of the forming steps, a very wide range ofprofiles can be produced with the methods according to the invention,wherein it is irrelevant whether the profile is open or closed sinceonly the order of the roll forming steps is important.

If technical features mentioned in any one of the claims are marked by areference number, these reference numbers have been merely included toimprove comprehensibility of the claims. Accordingly, these referencenumbers have no limiting effect on the scope of protection of eachelement indicated by way of example by such reference numbers.

1-14. (canceled)
 15. Method for producing a profiled metal sheet,comprising the following steps in the indicated order: a) roll formingat least part of a sheet metal strip by means of a roll forming unit,wherein the sheet metal strip determines a first working plane of theroll forming unit, in respect to which parts of the sheet metal stripare bent up to form the profiled metal sheet, and wherein the bent partsof the sheet metal strip are curved at least partially in respect to thefirst working plane; b) bending the profiled metal sheet by means of abending unit, wherein the bent up parts of the profiled metal sheet arebent such that a second working plane is formed, wherein the firstworking plane becomes curved; and c) roll forming at least part of theprofiled metal sheet by means of a roll fowling unit, wherein againparts of the profiled metal sheet are bent up in respect to the secondworking plane, and wherein the roll forming of step (c) while using asupporting measure.
 16. Method according to claim 15, wherein thesupporting measure is carried out at the first working plane in thatsupporting rollers or roller pairs are controlled along at least oneaxis so as to follow the height outline of the profile of the firstworking level or in that the first working level is placed or clamped ina kind of “negative mold” and guided through the roll forming unit on alinear guide.
 17. Method according to claim 15 further comprising thefollowing step after step c): d) bending the profiled metal sheet bymeans of a bending unit, wherein the first and the second working planeare at least partially curved.
 18. Method according to claim 15, whereinat least one dimension of the cross-section of the profiled metal sheetis kept constant.
 19. Method according to claim 15, wherein the bendingin step b) takes place on one plane.
 20. Method according to claim 17,wherein the bending in step d) takes place on one plane, on two planesor on three planes.
 21. Method according to claim 17, wherein thebending in step b) takes place on one plane and wherein the bending instep d) takes place on one plane, on two planes or on three planes. 22.Method according to claim 15, wherein the profiled metal sheets comprisethe following profiles: straight or bent profiles, U-shaped profileswith or without a flange, V-shaped profiles with or without a flange,C-shaped profiles, top-hat profiles, M-shaped profiles, oval profiles,rectangular profiles and combinations thereof.
 23. Method according toclaim 15, wherein the bending comprises a supporting measure.
 24. Methodaccording to claim 15, wherein the bending comprises 3-roller bending,glide bending, bending with form shoe, stretch-bending and combinationsthereof.
 25. Method according to one or more of claim 15, where pleatsare provided on profile sides in any desired position.
 26. Method forproducing a profiled metal sheet, comprising the following steps in theindicated order: a) roll forming a sheet metal strip by means of a rollforming unit, wherein the sheet metal strip determines a first workingplane of the roll forming unit, in respect to which parts of the sheetmetal strip are bent up to form the profiled metal sheet, wherein onedimension of the cross-section of the profiled metal sheet is keptconstant and wherein the bent up parts of the sheet metal strip arecurved at least partially in respect to the first working plane; b)bending the profiled metal sheet by means of a bending unit, wherein thebent parts of the profiled metal sheet are bent such that a secondworking plane is formed, wherein the first working plane becomes curvedand wherein again one dimension of the cross-section of the profiledmetal sheet is kept constant; and c) roll forming of the profiled metalsheet by means of a roll forming unit, wherein in respect to the secondworking plane again parts of the profiled metal sheet are bent up,wherein one dimension of the cross-section of the profiled metal sheetis kept constant and wherein the roll forming of step (c) while using asupporting measure.
 27. Profiled metal sheet, produced according toclaim 15, to be used in a branch of industry, comprising the automotiveindustry, especially for frame longitudinal and transverse members,bumpers, door stiffenings, preforms for inner high-pressure metalforming; in shipbuilding, particularly for masts; in road construction,especially for lanterns; and in architecture, especially for structuralsteel profiles.
 28. Profiled metal sheet, produced according to claim26, to be used in a branch of industry, comprising the automotiveindustry, especially for frame longitudinal and transverse members,bumpers, door stiffenings, preforms for inner high-pressure metalforming; in shipbuilding, particularly for masts; in road construction,especially for lanterns; and in architecture, especially for structuralsteel profiles.
 29. Method according to claim 15, wherein at least onedimension of the cross-section of the profiled metal sheet varies.